Insulated electric conductor and process of making same.



No. 687,5l7. Patented Nov. 26, IBM.

W. S. CLARK &. G. H. RUPLEY. INSULATED ELECTRIC CONDUCTOR AND PROCESS OF MAKING SAME.

{Application filed Dec. 15, 1899.)

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(No llodei.)

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No. 687,517. 7 Patented Nov. 26, I90l.

W. S. CLARK & (i. R. RUPLEY. INSULATED ELECTRIC CONDUCTOR AND PROCESS DFMAKING SAME.

(Application filed Dec. 15. 189R.)

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(No Model.)

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No. 687,5| 7. Patented Nov. 26, I90l.

W. S. CLARK & G. H. RUPLEY. INSULATED ELECTRIC CONDUCTOR AND PROCESS OF MAKING SAME.

(Application filed Dec. 15, 1899.) (No Nodal.) 4 Sheets-Sheet 3.

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No. 687,5!7. Patented Nov. 26, l90l. W. S. CLARK &. G. H. RUPLEY.

lNSULATED ELECTRIC CONDUCTOR AND PROCESS OF MAKING SAME.

{Application filed Dec. 15, 1899.] (No Modal.) 4 Sheets-Sheet 4.

UNITED STATES PATENT OFFICE.

'WALLACE S. CLARK AND GEORGE H. RUPLEY, OF SCIIENECTADY, NEIV YORK, ASSIGNORS TO THE GENERAL ELECTRIC COMPANY, A CORPO- RATION OF NEWV YORK.

INSULATED ELECTRIC CONDUCTOR AND PROCESS OF MAKING SAME.

SPEGlFICATION forming part of Letters Patent No. 687,517, dated November 26, 1901.

. Application filed December 15,1899. Serial No. 740,402. (No model.)

To all whom it may concern:

Be it known that we, WALLACE S. CLARK and GEORGE IIRUPLEY, citizens of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Insulated Electric Conductors and Processes of Making'the Same, (CaseNo.1,294,) of which the following is a specification.

The object of the present invention is to permit the manufacture of an electric conductor covered with a dense, coherent, elastic insulating material which may be applied so as to envelop the conductor when desired in a thin skin or film.

A further object of the invention is to cheapen the manufacture of insulated conductors and to enhance their insulating properties while reducing the space occupied by the insulation, thereby permitting a greater bulk of conducting material to be inclosed in a given space in electrical apparatus.

In carrying out our invention we place upon the conductor a uniform coating containing a compound of an amorphous or structureless cellulose and retard its drying after being applied to the conductor, thereby insuring a uniform thickness of the film or coating and intimate and uniform adhesion between the coating and the surface of the conductor; also, a toughening of the covering and absence of cracks due to uneven shrinkage. e employ a soluble compound of cellulose, to which we add a vehicle, which will combine'with the solvent, of slow drying or evaporating qualities relatively to the solvent and mix the ingredien'ts in such proportions as to form a compound fluid at the working temperature and lead the conductor into contact with the compound, whereby the latter is covered with a thin film, and as it is lead away from the bath or coating apparatus the coating is evenly distributed around the conductor and the latter then lead through a drying apparatus and wound upon a reel. We have obtained the best results thus far by employing a solution of pyroxylin in methyl alcohol, to which sufficient amyl acetate has been added to retard the drying. If the alcohol alone be employed as a solvent, its highly-volatile character permits an ineffective application of the amor phous cellulose compound to the conductor and leaves the coating in a poor condition to withstand service. A rapid drying tends to crack the coating, leaving it valueless as an insulating medium, particularly where exposed to water or damp air, and leaves it brittle and liable to crack and chip off under flexure of the conductor. The addition of the amyl acetate adds toughness to the coating and gives it an elasticity which prevents cracks in drying and permits it to withstand bending of the conductor.

Our invention, however, is not limited to the application of a solution of pyroxylin, butincludes also otheramorphous compounds of cellulose known to the arts, or pure structureless cellulose derived from cotton or other vegetable fiber, the essential feature of our invention being the application of a solution of an amorphous cellulose compound in such a Way as to render the compound non-brittle when dry.

Our invention may be carried out by the employment of a variety of apparatus but the form we have found effective in practice comprises a bath of coating material in which revolves a grooved wheel to pick up the insulating material, the top of the groove projecting above the bath, and devices for leading the conductor tangentially to the groove. By this organization good distribution of the coating material on the conductor is effected. The conductor is led to the grooved wheel from the supply-reel, and after being coated is carried through a drying box or chamber, and then passes through a testing-bath for locating anydefective spots in the insulation, after which it is Wound upon a receiving-reel ready for shipment.

Other novel features of our invention will be more fully described hereinafter and will be definitely indicated in the claims.

In the accompanying drawings is shown a convenient apparatus for carrying out our improvements. I

Figure 1 is a diagram showing the mode of procedure in insulating conductors according to our improvements. Fig. 2 is a plan view of a machine adapted to carry out the improvements. Fig. 3 is a side elevation of the same, and Fig. 4.- is an end elevation.

No claim, however, is herein made to the improvements in the machine, said matter being reserved for a companion application copending herewith and a division hereof, Serial No. tLSll, filed December 28, 1900.

Referring first to Fig. 1, 1 represents a supply-reel upon which the naked wire to be insulated is wound. From this reel the wire is led over a grooved wheel 2, mounted to revolve in a bath 3 of insulating com pound. The consistency of the compound will vary somewhat with the size of the conductor. For a very fine conductor a solution of twelve ounces of pyroxylin in thirty-six of methyl alcohol, to which has been added fifty-two of amyl acetate, gives effective results, permitting a suitable and effective coating on the conductor of about .0005 inch in thickness. The material is carried up from the bath in the peripheral groove of the wheel 2, any excess being scraped off from the edges of the groove by a scraper or knife 1. The conductor passes through the groove so as to bear upon its bottom, the groove being of sufficient depth to submerge the conductor in the insulating material carried around thereon. From this it will be evident that the material is not in a freely mobile fluid condition, but is sufficiently viscous to prevent rapid flowing away from the groove during the rotation of the wheel 2. A scraper 5 may be employed in the bath to remove the partiallydried accumulations of material from the groove. After the application to the wire by the wheel the material firmly adheres and floods all the parts of the surface, making an intimate contact therewith. The wire thus coated is led over a drying trough, which may be a chamber or a mere heated surface. This heater is indicated at 6 7, representing a row of gas-jets or other source of heat impinging on its under side. The conductor then passes over suitable guides and is led through a testingbath 8, which'may be mercury or water, after which it is wound upon a receiving-reel 9. The bath may be inclosed in a metal vessel electrically connected with a relay 10, controlling an alarm or other indicator 11. A. battery 12 or other source of electromotive force may be applied to the reel 1, so as to include the wire in the circuit. Thus when any break occurs in the insulation the testing-circuit is closed and the relay operated, giving notice to the workman that a defective point in the insulation is passing through the testing-bath, when it may be tagged for subsequent treatment.

Referring to Figs. 2, 3, and 4, which illustrate an assembled machine for carrying out the operations indicated in the diagram of Fig. 1, 13 represents a drive-shaft to which power may be applied by a pulley 14 and transmitting motion through a train of gears to the reel 9, mounted loosely on its shaft, but prevented from freely turning by a light friction-brake 15, the pressure of which may be varied by a set-screw, as indicated in Fig. 2. A train of gearing communicates motion to the shaft, on which is mounted the grooved coating-wheel 2, and to a guide-wheel 16 for leading or guiding the wire to the coatingwheel 2. Motion is communicated to a grooved feed-guide 17 for the receiving-reel 9, (see Figs. 2 and 4,) carried by a nut fed along a screw 18, to which a reciprocating motion is communicated by means of a straight and a crossed belt, respectively, (indicated at 19 and 20,) one or the other of which is thrown into clutch with the shaft on which the screw 18 is carried. The belts are alternately thrown into operation by a clutch 21, (see Figs. 2 and 4,) adapted to lock one or the other of the loose pulleys 22 23 to the screw-shaft. These pulleys are provided with a spider adapted to receive a projection on each side of the clutch 21. The clutch is shifted by a bar 2 1-, carried 011 a sliding rod 25, on which are fastened two collars 2o 26, alternately engaged by a projection 27 from the traveling nut on the screw-shaft 18. The position of these nuts may be controlled by a set-screw, so as to vary the length of receiving-reel on which the wire may be wound. A pivoted bar 28, carrying a roller 29, journaled in its free end, cooperates withadouble cam 30, fixedto the shaft 25 to hold the clutch 21 in engagement with the pulley to which it has last been connected until the last turn of wire on that layer is Wound, after which the arm 27 reaches the opposite limit of traverse and disconnects the clutch 21 from the pulley it engages and effects connection with the other pulley. The cam 30 and roller 29 permit the clutch to be shifted into engagement with the loose pulley and bear against the same under the thrust of roller 29 until the lateral projection can enter an opening in the spider or face of the pulley.

' \Vhat we claim as new, and desire to secure by Letters Patent of the United States, is-

l. The process of insulating electric conductors, consisting in coating the same with a thin film of amorphous cellulose compound in a slowly-drying solution.

2. The process of insulating electric conductors, consisting in coating the same witha solution of an amorphous cellulose compound in a volatile solvent, and retarding the drying of the applied compound.

3. The process of insulating electric conductors, consisting in coating the same with amorphous cellulose compound treated with a solvent containing amyl acetate.

4:. The process of insulating electric conductors, consisting in coating the same with a thin film of a liquid cellulose compound mixed with a toughening material.

5. The process of insulating electric conductors, consisting in coating the same with a solution of pyroxylin containing amyl acctate.

6. The process of insulating electric con of homogeneous amorphous cellulose compound.

10. An electric conductor coated with a thin film of homogeneous amorphous cellulose compound and amyl acetate.

11. An insulating compound for electric conductors consisting of a liquid structureless cellulose compound containing a toughening material.

In Witness whereof We have hereunto set our hands this 13th day of December, 1899.

WVALLAOE S. CLARK. GEORGE H. RUPLEY. Witnesses:

BENJAMIN B. HULL, JosEPH Guoss. 

